Shot peening machine

ABSTRACT

A SHOT PEENING MACHINE PROVIDING A HOUSING CIRCUMSCRIBING A PEENING CHAMBER HAVING MEANS FOR SUPPORTING A WORKPIECE WITHIN THE CHAMBER AND SHOT DISCHARGE MEANS MOVABLY MOUNTED ON THE HOUSING FOR RECIPROCAL MOVEMENT ALONG A SUBSTANTIALLY RETILINEAR PATH TO DISCHARGE SHOT INTO THE CHAMBER AGAINST THE WORKPIECE.

Dec. 14, 1971 w, ARMEY SHOT PEENING MACHINE 4 Sheets-Sheet 1 Filed June 1, 1970 RUTTER W. ARMS) WfM A TTORNEVS Dec. 1-4, 1971 R. w. ARMEY 5 7 SHOT PEENING MACHINE Filed June 1, 1970 4 Sheets-Sheet a as ,ezpg 45 [76 RU77'ER w ARMEV INVf 70,?

A TTORNE Dec. 14, 1971 R. w. ARMEY 3,626,539

snow PEENING MACHINE Filed June 1, 1970 v 4 Sheets-Sheet 5 I76 RUTTER w. ARMEY INVENI'OP A TTORNEVS Dec. 14, 1971 w, ARMEY 3,626,539

SHOT PEENING MACHINE Filed June 1, 1970 4 Sheets-Sheet 4 RU 775/? w ARMEV IN VE N 70A A TTORNEVS United States Patent O 3,626,539 SHOT PEENIN G MACHINE Rutter W. Armey, 5505 E. Liberty Ave., Fresno, Calif. 93727 Filed June 1, 1970, Ser. No. 42,193 Int. Cl. B24c 3/10 US. Cl. -95 9 Claims ABSTRACT OF THE DISCLOSURE A shot peening machine providing a housing circumscribing a peening chamber having means for supporting a workpiece within the chamber and shot discharge means movably mounted on the housing for reciprocal movement along a substantially rectilinear path to discharge shot into the chamber against the workpiece.

BACKGROUND OF THE INVENTION It has become the practice lightly to strike metal articles of manufacture such as engine crankshafts and the like with a plurality of relatively fine steel balls or shot to clean and to provide a more compact grain structure near the surface for imparting additional strength to the article. This is conventionally accomplished by a relatively large machine having at least one stationary shot discharge head extended into a housing forming a peening chamber. The workpiece is traveled on an elongated conveyor past the head and through a curtain of shot discharged therefrom. Other machines for the purpose employ a plurality of shot discharge heads where the articles to be peened are of a size, such as an aircraft wing or the like, not adapted for conveyance past a single discharge head. It has been difficult conveniently to peen all sides of the article during a single operation because of the problems in disposing the shot discharge heads on opposite sides of the article in non-interfering relation. Mechanisms have been provided for rotating a workpiece which require complicated clamping and drive systems which heretofore have not been practically applied. However, when peening engine crankshafts and the like having many irregular surfaces, it has been difficult evenly to distribute the shot over the entire surface of the crankshaft and particularly those areas which are normally shielded by the overhanging throw portions of the crank. Furthermore, such prior machines have been prohibitively expensive for all but the largest machine shops.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved shot peening machine.

Another object is to provide such an improved shot peening machine which is able to peen irregularly shaped articles such as engine crankshafts and the like.

Another object is to provide a shot peening machine which can peen relatively large articles without being excessively large itself.

Another object is to provide an improved shot peening machine of the character described which is capable of conveniently and economically peening virtually any article irrespective of its configuration.

Another object is to provide an improved shot peening machine more effectively utilizing a shot discharging head.

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Another object is to provide an improved shot peening machine in which the single shot discharge head is reciprocated along a substantially rectilinear path adjacent to the workpiece within the peening chamber.

Another object is to provide an improved shot peening machine which has a workpiece support frame adapted to rotate the workpiece without requiring any workpiece clamping mechanism.

Another object is to provide an improved shot peening machine in which the workpiece support frame is effective concurrently to oscillate the workpiece during rotation thereof so as to vary the angle of impingement of shot thereagainst and to afford full exposure of the normally shielded areas of the workpiece to the shot discharged by the shot discharge head.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a shot peening machine embodying the principles of the present invention.

FIG. 2 is a top plan view of the shot peening machine.

FIG. 3 is a somewhat enlarged fragmentary end elevation of the shot peening machine showing a mechanism for oscillating the workpiece support frame within the machine.

FIG. 4 is a somewhat enlarged transverse vertical section taken generally on line 44 of FIG. 1.

FIG. 5 is a longitudinal vertical section through the shot peening machine, taken generally on line 5-5 of FIG. 2, with portions broken away for illustrative convenience.

FIG. 6 is a somewhat enlarged perspective of the workpiece support frame removed from the peening chamber of the shot peening machine of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, a shot peening machine embodying the principles of the present invention provides an elongated housing 10 supported in elevationally spaced relation to a floor surface 11 by a plurality of corner legs 12. The housing includes opposite front and rear walls 14 and 15, respectively, which are interconnected by opposed top and bottom walls 17 and 18. respectively, and opposite end walls 19. The walls circumscribe an elongated peening chamber 20 with access thereto being provided by an elongated opening 22 in the front wall 14. The opening is selectively closed by an elongated door 25 swingable about a hinge 26 along its lower edge.

The bottom wall 18 of the housing 10 has a pair of opposite downwardly inclined panels 27 and 28 individually providing lower continuations of the front and rear walls 14 and 15, respectively. The bottom panels provide lower spaced ends which terminate in outwardly turned flanges 30 and 31, respectively, which define therebetween an elongated substantially rectangular slot 32. The inner surfaces of the walls of the housing are lined with a sound-dampening and energy absorbing sheet material, such as rubber or the like, against which the shot within the peening chamber is rebounded downwardly toward the bottom panels and discharge slot 32. The top wall 17 of the housing provides an elongated substantially rectangular opening 35 cloesly adjacent to the top edge of the door in the front wall 14.

A pair of elongated channular beams 37 are mounted on the top wall 17 of the housing 10 between the end walls in spaced substantially parallel relation individually along the opposite sides of the opening to define an elongated guide slot 38 above the opening. An elongated head mounting plate 40 is supported in upwardly spaced substantially parallel relation to the top wall 17 of the housing 10 on the innermost channular beam 37 and an extension 42 of the rear wall 15 of the housing. A pair of elongated spaced substantially parallel guide tracks 45 are mounted on the upper surface of the head mounting plate. Each of the guide tracks is constructed of an elongated rail of triangular cross section providing an upper apex with downwardly diverging sides 47 secured, as by welding or the like, to base plate 48.

A carriage plate 50 is disposed for movement in a predetermined path above the head mounting plate 40. A

plurality of sets of guide rollers 51 are mounted in depending relation from the carriage plate 50 for rolling engagement with the guide tracks 45. In order to provide maximum stability and to insure that the carriage is virtually free of any tendency to bind, the sets of rollers 51 are disposed in a triangularly spaced arrangement. Two sets of rollers are disposed on the innermost guide track 45 and a single set of rollers engages the outermost guide track 45 adjacent to the rear wall 15 at a point substantially midway between the spaced rollers on the opposite innermost guide track. Each set of the guide rollers 51 provides a mounting post 52 having a pair of rollers 53 rotatably mounted thereon for rotation about axes disposed in substantially right-angular 90 relation. Ac

cordingly, the guide rollers are rollably engageable with their respectively associated opposite sides of the guide tracks so as positively to preclude any lateral shifting movement of the carriage plate 50 in a plane normal to the longitudinal direction of movement of the plate along the guide tracks 45.

The carriage plate 50 is reciprocated along the guide tracks 45 by a screw drive mechanism generally indicated by the reference numeral 55. This mechanism provides a travel block 56 having a screw-threaded bore 57 therethrough which is mounted in depending relation from the carriage plate substantially intermediate the guide tracks 45. An elongated screw-threaded rod 58 is extended through the travel block and its ends are rotatably journaled in bearing blocks 60 mounted at the ends of the mounting plate 40 substantially centrally between the guide tracks 45. One end of the threaded rod is extended through its respective bearing block to mount a sprocket 62 which is disposed in spaced, coplanar relation with a drive sprocket 64 about which is trained an endless drive chain 65. The drive sprocket is mounted on a motor 67 supported on a platform 68 outwardly extended from the associated end wall 19 of the housing 10.

A shot discharge head, generally indicated by the reference numeral 70, is mounted on the carriage plate 51 and is extended through a substantially rectangular opening 72 in the carriage plate 50 for movement through the elongated guide slot 38 between the beams 37 above the opening 35 in the top wall 17 of the housing 10. The discharge head provides a substantially rectangular boxlike structure having predetermined forward and rearward walls 74 and 75, respectively, opposite end walls 76, and a removable top wall 77 releasably secured thereto by a plurality of bolt and nut assemblies 78. The front and rear walls of the head are disposed in sliding relation to the inner surfaces of the channular beams 37 with the head providing a lower edge 80 disposed in substantially coplanar relation with the top wall 17 of the housing.

A powered centrifugal shot discharge turbine is mounted within the shot discharge head 70 and has an axially extended inlet conduit projecting outwardly through the front wall 74 of the head. The inlet supply conduit for the turbine is arcuately upwardly curved and is held in closely spaced relation to the front wall of the discharge head by a bracket 87. A substantially flat funnel-shaped hopper is mounted on the bracket in communicating relation with the upper end of the shot supply conduit 86 and provides a relatively wide upper open end 92. The turbine 85 is driven through a drive shaft bearing block by an electric motor 97 connected thereto by a pulley and V-belt assembly 98. The bearing block and drive motor are rigidly mounted on the upper surface of the carriage plate 50, the combined weight of which is carried directly over the guide tracks 45 and guide rollers 50. The turbine 85 further includes a convolute shot discharge spraying ramp 100 which is downwardly extended through the discharge head and terminates in a relatively wide lower end 102 adjacent to the opening 35 in the top wall 17 of the housing 10.

As best shown in FIG. 5, a closure panel mounting drum 105 is disposed on each of the end walls 19 of the housing 10 adjacent to a slot 106 through the end wall aligned with the lower edge of the shot discharge head 70. Each of the drums is journaled at its opposite ends in a pair of bearing blocks 109 secured to the end walls of the housing 10. An elongated substantially flat flexible closure panel 110 is rolled upon its respective drum and includes a distal end 112 connected to a bracket 114 on the end wall 76 of the shot discharge head 70 adjacent to its lower edge 80. The closure panels 110 are oppositely extended from the shot discharge head 70 in masking relation to the opening 35 in the top wall 17 of the housing 10 during reciprocation of the shot discharge head between the opposite end walls 19 of the housing. Accordingly, while one panel is being extended from its respective drum 105, the opposite panel is being retracted and rolled upon its respective drum.

The described retraction of the closure panel 110 at the right-hand end of the machine, as viewed in FIG. 2, is provided by a weight mechanism generally indicated by the reference numeral 120. This mechanism is best shown in FIG. 3 and provides a pulley drum '122 which is rotatably journaled in a pair of bearing blocks 124 secured to the end wall of the housing adjacent to one of the bearing blocks 109 of the panel mounting drum 105. The pulley drum 122 is rotatably connected to the panel drum 105 by a universal coupling 126 and the drum mounts in winding relation thereon an elongated cable 130. The portion of the cable extended from the pulley drum 122 is trained over an idler pulley 132 supported above the end wall of the housing by an arm 134. A second idler pulley 135 is mounted on an angularly extended arm 136 adjacent to the rearward wall 15 of the housing 10. The cable is trained over and downwardly extended from the second idler pulley 135 in supporting relation to a weight 140 providing a suflicient force for retracting the associated closure panel on its respective drum ahead of the shot discharge head during its movement toward that particular panel mounting drum.

The closure panel mounting drum 105 at the left-hand end of the machine, as viewed in FIGS. 2 and 5, provides a similar cable drum 142 secured for rotation upon the end wall 19 of the housing 10 by a pair of bearing blocks 143 which is driven by the adjacent panel drum through a universal coupling 146. A cable is wound about the cable drum 142 and is trained over an outboard idler pulley 152 rotatably supported on a pair of arms 153 extended outwardly from the end Wall of the housing. The end of the cable supports a weight 155 similar to the weight 140 for providing a retractive force on its associated closure panel 110 during movement of the shot discharge head 70 in the direction of its respective mounting drum.

An elongated shot accumulating conveyor trough providing flanged edges 162 is mounted on the bottom wall 18 of the housing 10 beneath the elongated slot 32.

An elongated screw conveyor 165 is rotatably mounted within the trough and provides a pair of opposite helically wound blades 167 which are effective to move the shot accumulated therein toward an open center chamber 168. As best shown in FIG. 3, the accumulating conveyor is adapted to be power driven by an electric motor 170 through a pulley and V-belt assembly 172.

An elongated transfer conveyor 175 provides a lower end 176 connected to the center chamber 168 of the conveyor trough 160 and is rearwardly upwardly extended therefrom to terminate in an opposite upper discharge end 177. The transfer conveyor includes a helically wound blade 178 which is driven by an electric motor 180 through a pulley and V-belt assembly 182. An elongated upwardly extended shot elevating conveyor is mounted on the floor surface 11 rearwardly adjacent to the machine and in shot receiving adjacent relation to the discharge end 177 of the transfer conveyor 175. The elevating conveyor has a chain and bucket arrangement 187 which is driven by an electric motor 188 through a pulley and V-belt mechanism 190. The upper discharge end of the elevating conveyor discharges the shot downwardly therefrom through an elongated supply tube 192 having a lower discharge end loosely extendible into the upper open end of the hopper 90 on the shot discharge head 70. The supply tube 192 is constructed of rubber, plastic or other suitable flexible material to permit the tubing to flex sufficiently so as to follow the discharge head during its reciprocation between the ends of the housing 10.

In order to preclude choking of the discharge slot 32 between the panels 27 of the bottom wall 18 of the housing, an elongated baflie plate 195 is mounted between the ends of the housing directly above the slot and the discharge conveyor 165. Like the inner surfaces of the walls of the housing 10, the bafiie plate has a coating of rubber or other cushioning material and is provided with angularly downwardly converging surfaces to insure that shot is deflected against the adjacent downwardly inclined panels of the bottom wall and then into the discharge conveyor trough 160.

A workpiece support frame 200 is disposed within the peening chamber 20 inside the housing 10 for rotationally supporting a workpiece such as the engine crankshaft indicated by the reference numeral 202 in FIG. 4. As best shown in FIG. 6, the workpiece support frame provides a pair of opposite substantially triangular end plates 205 having a lower corner 206 and substantially equally spaced upper corners 208. A pair of elongated rods 210 are individually freely rotatably mounted between the corresponding upper corner of the end plates and a drive rod 212 is rotatably mounted between the lower corners 206 of the end plate. The ends of the drive rod are journaled in their respective opposite end walls of the housing to mount the support frame for limited oscillating movement within the peening chamber of the housing. The right-hand end of the drive rod 212 is extended through and outwardly from its associated end wall of the housing, as best shown in FIG. 5, to mount a sprocket 214 in outwardly spaced relation from the end wall. The sprocket is adapted to be driven by an elongated endless chain 215 which is also trained about a drive sprocket 217 on the drive shaft 218 of a powered gear box 219. The gear box is driven by an electric drive motor 220 through a pulley and V-belt drive mechanism 221.

A plurality of flexible endless belts 222 are loosely disposed in circumscribing relation about the upper rods 210 and lower drive rod 212 for circuitous movement thereabout during rotation of the lower drive rod. The belts can be initially longitudinally slid along the rods in any desired spaced relation depending upon the particular spacing of the bearing surfaces of the workpiece being supported. The belts provide upper runs 223 extending between the upper support rods which are adapted to receive and support the crankshaft 204, as shown in FIG. 4, in cradling belt tensioning relation. Accordingly,

the workpiece serves to tighten the belts sufficiently against the drive rod for imparting a positive drive therebetween to rotate the workpiece.

An elongated sleeve 225 is journaled upon the outer extended end of the drive rod 212 and has its inner end rigidly secured to the lower corner 206 of the adjacent end plate 205 of the frame 200 as by welding or the like. An elongated arm 226 is upwardly extended from the outer end of the sleeve. The arm is pivotally connected at its upper end to a reciprocating arm 228 having its opposite end pivotally mounted on an eccentric drive plate 230. The drive plate is supported on the outer end of the gear box drive shaft 218 adjacent to the drive sprocket 217. The eccentric drive plate, however, can be selectively disconnected in order to permit locking of the support frame 200 in any desired position within the peening chamber by an elongated handle 232 connected to the sleeve 225 inwardly adjacent to the arm 226 which has a locking bolt 234 extendible into a locking bore 235 in the adjacent end wall of the housing. The lock bolt 234 is permitted arcuate swinging movement along an arcuate slide plate 236 in the adjacent end wall of the housing when the eccentric drive plate is connected for oscillating the entire workpiece support frame 200.

An electrical control panel 240 is conveniently mounted on the front wall 14 of the housing 10 adjacent to the left-hand end of the access door 25, as shown in FIG. 1. The panel provides individual control buttons for the various electric motors previously described which drive the numerous components of the machine of the present invention. The electrical control system includes appropriate limit switches, one of which is indicated by the reference numeral 242, disposed along the guide tracks 45 which are connected to the carriage drive motor 67 associated with the screw-threaded drive rod 58. Such limit switches, which may be selectively longitudinally adjusted along the guide track in corresponding relation to the particular length of workpiece to be peened within the machine, are operative to reverse the direction of movement of the shot discharge head 70 along the guide tracks and to shut off the carriage drive motor 67 upon completion of each reciprocating sequence of operation.

An air exhaust pipe 245 is extended through the front Wall of the housing adjacent to the right-hand end of the door 25, as shown in FIG. 1, which is connected to a suitable suction fan, not shown, for exhausting dust from the peening chamber 20.

OPERATION The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. As described, access to the peening chamber 20 is provided by opening the door 25 in the front wall 14 of the housing by swinging the door outwardly dovmwardly about its hinge 26. A work piece, such as the crankshaft 204, is inserted through the door opening and is rested upon the upper runs of the support belts 222 on the support frame 200. It will be noted that prior to insertion of the crankshaft, the bearin g portions thereof are masked with a suitable rubberized tape to preclude peening or scratching of the ground surfaces thereof. As also described, the belts 222 can be slid longitudinally in any desired spaced relation upon the support rods so as to be precisely aligned with the desired bearing surfaces of the particular workpiece within the peen ng chamber.

The appropriate electric control buttons on the control panel 240 are actuated to energize the variously described drive motors for the shot discharge turbine on the discharge head 70 and for the conveyors 165, 175 and 185. The relatively fine shot discharged from the turbine 85 is thrown downwardly along the channular spray ramp which propels the shot in a relatively wide curtain into the peening chamber against the crankshaft 204. After engagement of the shot with the workpiece, it gravitates downwardly along the lower inclined panels of the bottom Wall where it is collected by the collecting conveyor 165 and where the oppositely wound blades 167 convey the shot to the center chamber 168. The shot is then picked up by the transfer conveyor 175 and directed into the housing of the elevating conveyor 185 where it is conveyed upwardly to the upper discharge end thereof and exhausted into the shot supply tube 192. The shot is discharged from the tube into the elongated hopper 90 for re-entry into the discharge turbine 85 through the inlet conduit 86. Accordingly, a continuous supply of the shot is provided by the recirculating system of collecting transfer and elevating conveyors.

Subsequent to actuation of the shot discharge turbine 85, the drive motor associated with the drive rod 58 is energized to travel the carriage 43 along the guide tracks 45 to motivate the shot discharge head 70 initially from left to right, as viewed in FIG. 1, along the opening 35 in the top wall of the housing. At the same time, the drive rod 212 of the workpiece support frame is rotated to travel the support belts 222 around the frame to rotate the crankshaft rested upon the upper runs thereof. The support frame 200 is concurrently oscillated by connection of the eccentric drive plate 230 with the reciprocating arm 228 and the arm 226 of the sleeve 225. As described, during such oscillation, the loosened lock bolt 234 of the handle 232 is permitted to slide through the arcuate slot 236 in the end wall of the housing.

While the crankshaft 204 is being rotated and oscillated transversely of the longitudinal axis of the support frame, the traversing shot discharge head 70 causes the curtain of shot discharged from the spray ramp 100 to sweep along the length of the crankshaft in such a manner that virtually all portions of the crankshaft which are not masked are engaged by the shot. Such compound rotational and oscillatory movement of the frame and workpiece insures that even the most inaccessible areas of the workpiece are exposed to the sweeping curtain of shot discharged from the turbine 85. It is significant that during the described travel of the shot discharge head 70 along the guide tracks 45, the closure panels 110 maintain the peening chamber 20 in a substantially sealed condition precluding the escape of shot through the opening 35 in the top wall of the housing by their alternate extension and retraction from their respective mounting drums 105 in response to such movement of the discharge head 70.

When the shot discharge head 70 reaches its extreme right-hand position, as viewed in FIG. 1, the limit switches 242 of the electrical control system are effective to reverse the drive to cause the head to return to the left to its initial starting position of FIG. 1. During such return movement, the right-hand closure panel 110 is pulled by the discharge head from its respective drum 105 while the opposite left-hand panel is retracted and rolled upon its respective drum by the gravitational pull exerted by its associated weight 155. It is further significant that the triangular arrangement of the rollers 50 of the carriage 43 provides substantially unrestricted reciprocal movement of the shot discharge head 70 by precluding any tendency for lateral shifting of the head and carriage from the desired rectilinear path. Accordingly, the lower end of the discharge head is permitted to slide between the beams 37 without any sticking or binding therein.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved shot peening machine which is adapted to utilize a single shot discharging turbine with a reciprocal carriage mounting which eliminates the need for any additional discharge heads as conventionally required by such machines. The effectiveness of the use of a single discharge head is further enhanced by the workpiece support frame which gently cradles the workpiece on the upper runs of the traveling belts without complicated clamping mechanisms which, in conventional machines, tend to mar or damage 8 the ground surfaces of the workpiece. The support frame not only rotates the workpiece but imparts an additional oscillatory movement to the workpiece transversely of the support frame and path of travel of the shot discharge head to insure full exposure of all areas of the workpiece to the shot.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A shot peening machine comprising a housing circumscribing a peening chamber, means for supporting a workpiece within the chamber, shot discharge means movably mounted on said housing for reciprocal movement along a substantially rectilinear path to discharge shot into the chamber against the workpiece, and means for oscillating said support means and said workpiece thereon transversely of said path.

2. The shot peening machine of claim 1 in which said support means is adapted to rotate the workpiece about an axis substantially parallel to said path of movement of the shot discharge means concurrently with said oscillation of the support means.

3. The shot peening machine of claim 1 in which said support means comprises a frame having a plurality of elongated spaced substantially parallel rotatable rods, and a plurality of endless belts circumscribing the rods in longitudinally spaced relation providing upper runs adapted to support the workpiece in cradling relation thereon.

4. The shot peening machine of claim 3 in which said frame comprises a pair of opposite substantially flat end plates of triangular configuration, said rods having ends journalled in the plates, and powered means drivingly connected to a rod for traveling the belts around the rods and rotating the workpiece.

5. The shot peening machine of claim 4 in which said end plates include spaced rod mounting corners arranged to position a pair of the rods in an upwardly disposed spaced substantially parallel common horizontal plane above said rod driven by said powered means, and means for oscillating said frame about said driven rod during said travel of the belts about the rods.

6. The shot peening machine of claim 5 in which said driven rod includes endward extensions journaled in the housing, a sleeve circumscribing one of said extensions and connected to the adjacent end plate of the frame, and an oscillating drive mechanism on the housing operationally connected to said sleeve.

7. A shot peening machine comprising an elongated housing having top, bottom, end and side walls circumscribing a peening compartment; means for rotatably supporting a workpiece within the compartment, there being an elongated opening through said top wall of the housing; a shot discharge head mounted on said top wall of the housing for reciprocal movement in a predetermined rectilinear path along said opening and having a shot spraying ramp extended through said opening into said chamber to discharge shot against the entire surface of the workpiece; a shot circulating system providing a shot accumulating conveyor in said bottom wall of the housing, a transfer conveyor upwardly extended from said accumulating conveyor and having an upper discharge end above said housing, and an elongated flexible discharge tube connected to said upper end of the transfer conveyor and having an end disposed in following continuously shot feeding relation to said shot discharge head; and means for oscillating said support means and said workpiece thereon transversely of said path. .h

8. A shot peening machine comprising a housing hav- References Cited ing a chamber, means for supporting an elongated work- UNITED STATES PATENTS piece within the chamber, shot discharge means mounted for reciprocal movement along a path longtudinally guchs et 51 14 X arpenter, Jr. 51-9 of the workpiece to discharge shot against the work- 5 2933 802 4/1960 Fuchs X piece, and means for Oscillating Said Support means and if X WOYkPiece transversely Said Path- 2:719:387 10/1955 Fahrney Ill 51-15 9. The shot peening machine of claim 8 in which the support means includes means for gravitationally sup- LEON G-MAcHLINPnmarY Exammer porting the workpiece and rotating it about an axis sub- 10 U3, C1, X R

stantially parallel to the path. 29-90;72--53 

